Electrical connection



Oct. 18, 1955 M. P. A. BEERS ELECTRICAL CONNECTION Filed Oct. 10, 1951 INVENTOR Gerurdus Marcus Perrus A drionus Beers United States Patent ELECTRICAL CONNECTION Gerardus Marcus Petrus Adrianus Beers, Hilversum, Netherlands, assignor to Hartford National Bank and Trust Company, Hartford, Conn., as trustee Application October 10, 1951, Serial No. 250,651

Claims priority, application Netherlands October 21, 1950 3 Claims. (Cl. 339-276) This invention relates to the electrical connection between a wire and a plate-shaped connecting body, such as a contact spring of a relay, a tag-shaped supply terminal or the like. It also relates to improved connecting bodies suitable for such a connection. The object of the invention is to provide a construction which is particularly eflicient from both the electrical and mechanical points of view.

According to the invention, the plate-shaped connecting body has formed in it a slot in which part of the wire extends in the longitudinal direction thereof, the said slot comprising a number of local constrictions formed by teeth which are deformed by a jumping-up operation so as to grip the inserted wire.

The connection according to the invention is an improvement upon known connections since it provides a particularly efficient and persisting electric contact, as will be explained hereinafter, whilst the jumping-up of the teeth provides mechanical strengthening of the contact zone, and thus a robust connection.

In addition, the plate-shaped connecting body which has formed in it a slot comprising a number of local constrictions, formed by teeth, is particularly suitable for mass production, because it can be manufactured by a single mechanical operation, such for example as punching or stamping.

The slot preferably comprises a series of substantially circular, interconnected apertures.

In order that the invention may be clearly understood and readily carried into effect, it will now be described in greater detail with reference to the accompanying drawing, in which Fig. 1 is a plan view of a contact spring for a relay, one of the ends being provided with an electric connection according to the invention.

Fig. 2 shows, on an enlarged scale, part of the slot in the contact spring of Fig. l, and

Fig. 3 is an enlarged cross-sectional view of a contact joint.

Referring to Fig. 1, a contact strip 1 of a relay has formed in one of its ends a slot 2 which comprises a number of local constrictions. The opposed teeth formed by the local constrictions are designated 3, 3' in the figure. The slot comprises five interconnected apertures circumscribed by intersecting circles. Part of the slot thus formed is shown on an enlarged scale in Fig. 2. The spacings between the centres of the circular apertures 4 are such that the spacing d between the opposed teeth 3, 3' is at least equal to the diameter of the wire 5 to be inserted.

In securing the wire 5 to the strip 1, the wire is inserted between the teeth 3, 3' in a longitudinal direction. The teeth 3, 3' are then pinched at the levels 6, 6' with the use of a pair of tongs the jaws of which are normal to the plane of the connecting body and are parallel to the Wire, and the teeth are thus jumped-up. This jumping-up operation has the etfect of forcing them towards each other and deforming them in such manner as to grip the wire in part. The tips of the teeth tend to penetrate into the surface of the wire and hence rupture any oxide film that may be present.

Fig. 3 is an enlarged cross-sectional view of two opposed teeth 3, 3', the broken lines showing the shape of the teeth prior to deformation. The drawing shows clearly the constrictions in the teeth brought about by the jaws of the pair of tongs at the levels 6, 6'. The material originally enclosed between the surfaces of these constrictions and the initial surfaces shown by the broken lines is pressed about the wire 5 so that, as may be seen from the figure, the teeth 3, 3' engage the wire 5 laterally, a large surface area of contact being thus produced.

The requirements of an efiicient contact, namely a clean contact surface, a high contact pressure and a large contact area are thus wholly satisfied.

In the embodiment shown the teeth formed by the edges of the slot are circumscribed by parts of circular apertures. However, the teeth may have any other suitable shape, for axample they may be of sawtooth form or trapezoidal.

What I claim is:

1. An electrical connection comprising a wire and a flat metal connecting strip being provided with a slot having a plurality of spaced, opposed teeth therein, part of said wire being inserted in said slot and extending in the plane of said fiat metal connecting strip whereby when lateral pressure is directly applied to opposite sides of each of said teeth and in a direction perpendicular to said plane of said strip, said teeth are deformed thereby gripping a substantial portion of the periphery of said part of the wire.

2. An electrical connection as claimed in claim 1 wherein said slot is formed by a plurality of substantially circular, interconnected apertures.

3. An electrical connection as claimed in claim 1 wherein said slot is formed by a plurality of substantially circular, interconnected apertures, and said circular circumscriptions of said apertures intersect.

References Cited in the file of this patent UNITED STATES PATENTS 1,942,661 Paulus Jan. 9, 1934 2,266,593 Emmons Dec. 16, 1941 2,375,068 Bennett May 1, 1945 2,463,580 Warshyk et a1. Mar. 8, 1949 2,476,795 Avigdor July 19, 1949 2,572,956 Servis Oct. 30, 1951 

